Racket

ABSTRACT

A racket having a pair of stringed ball-engaging surfaces wherein one of said surfaces is &#39;&#39;&#39;&#39;smooth&#39;&#39;&#39;&#39; while the other surface is &#39;&#39;&#39;&#39;rough&#39;&#39;&#39;&#39; whereby different amounts of spin may be imparted to a ball depending on which racket surface is presented to the ball.

United States Patent DeLorean 1 Dec. 16, 1975 1 1 RACKET 2,793,1365/1957 R00! 273/167 J x D X 75 Inventor: John Z. DeLorean, BloomfieldH1115, 9/1968 273m Mich. FOREIGN PATENTS OR APPLICATIONS 73 A I h547,946 9/1942 United Kingdom 273/73 D 1 Sslgnee g g gg g s ggfi 781,5832/1935 France 273/76 1,173,824 4/1958 Germany 273/76 [22] Filed: July 5,1974 1,314 l/1884 United Kingdom.... 273/73 D 25,019 11/1911 UnitedKingdom..... 273/73 D 1 PP 436,252 428,582 5/1935 United Kingdom 273/761,062,796 3/1967 United Kingdom 273/167 J 52 us. 01 273/73 1) 51 im. C1A63B 51/02 Primary hammer-Wham P Y 58 Field 61 Search... 273/29 A, 72 R,73 R, 73 c, Attorney, Agent, Firm-136mg, Ethmgton, 273/73 D, 73 E, 73 L,76, 167 J Barnard, Perry & Brooks [56] References Cited [57] ABSTRACTUNITED STATES PATENTS A racket having a pair of stringed ball-engagingsur- 703,519 7/1902 Becker 273/76 faces wherein one of said surfaces issmooth while 763,059 6/1904 Hyde 273/73 D the other surface is roughwhereby different 771,247 10/1904 Hillerich 273/72 R amounts of spin maybe imparted to a ball depending 1,531,778 3/1925 Gallaudet 273/73 D onwhich racket Surface is presented to the ha 1,970,376 8/1934Hamburger... 273/73 D X 2,080,642 5/1937 Timpe 273/73 D 9 Claims, 6Drawing Figures US. Patent Dec. 16, 1975 392,431

RACKET BACKGROUND OF THE INVENTION 1. Field of the Invention In gamesusing a racket to strike a ball, part of the technique of play normallyinvolves certain shots wherein it is desired to impart a controlled spinto the ball both to change its flight pattern as well as bouncingcharacteristics. In other words, it is common to impart top spin orunderspin depending on the type of shot the player is seeking toexecute. For example, it is normal when a player is making his secondserve in tennis, to strike the ball more softly than a first serve butat the same time imparting extra spin to the ball to cause the same tohave an accentuated hop toward or away from the receiving player, makingthe same more difficult to return. On other occasions, when the opposingplayer is deep in his back court, it is common to provide an underspinto the volley, causing the ball to tend to stop or slow down close tothe net and achieving what is known as a drop shot.

Thus, being able to control the amount and direction of spin imparted tothe ball is an important part of playing strategy in all racket games.

A player varies the spin by the manner in which racket contact is madewith the ball. The maximum speed and minimum spin is imparted to a ballwhen the racket face is approximately at 90 to the flight of the ball atthe time of impact. On the other hand, maximum spin is imparted when theracket face has a significant amount of tangential movement relative tothe ball at the time of impact. Since both racket faces are normally ofrelatively the same smoothness, varying the amount of spin imparted tothe ball requires excellent racket control by the player.

2. Description of the Prior Art Insofar as the present invention isconcerned, no prior art devices are known wherein the racket stringsurfaces are constructed in such a manner that one surface is actuallyformed or otherwise treated so as to be rougher than the other so as tofacilitate or significantly change the amount of spin imparted to theball depending on which side of the racket makes impact with the ball.

SUMMARY OF THE INVENTION In the present invention a racket is providedwherein the string surfaces constituting one of the racket faces is ofsuch a character as to impart substantially more spin to the ball thanwould be possible with a similar stroke on the opposite face. Theessence of the present invention is to provide two racket faces, one ofwhich is substantially rougher than the other face, thereby enabling theplayer to hit the ball with far more spin with one face than the other.

The intended result is achieved by forming or otherwise treating theracket strings in such a way that one face of the racket has asubstantially greater coefficient of friction than the other. While therougher face is visible to the eye, it is more readily determinable tothe player by brushing his free hand across one of the racket stringfaces.

In the present invention the desired result is illustrated in basicallytwo different ways. In one variation of the invention, the stringelement itself is preformed with such a cross-sectional configurationthat one side of the string has a relatively flat smooth surface whereasthe opposite portion of the string has a relatively narrow or sharpsurface. In this case, the racket frame includes string receivinggrooves or holes having cross sections identical in shape and size tothe formed string whereby the flat portions thereof are presented on oneface of the racket and the sharp portions on the other face.

In another variation of the invention the string element is ofconventional shape, e.g. generally circular in cross section, with oneface having an abrasive or particulate material applied thereto so as tocreate a relatively rough surface as compared with the other portion ofthe string element which is untreated.

Referring now to the invention as depicted in the drawings:

FIG. 1 is a partial elevational view of a racket head embodying theinvention;

FIG. 2 is a sectional view along lines 2-2 of FIG. 1;

FIG. 3 is a sectional view through the racket frame along lines 33 ofFIG. 2; 7

FIG. 4 is an elevational section through a part of a racket frameshowing another modification of the invention;

FIG. 5 is a sectional view through the racket frame along lines 55 ofFIG. 4; and

FIG. 6 is a further modification of the invention.

As seen in FIG. 1, a tennis racket is indicated generally at 10 andincludes a frame member 12 and a plurality of interwoven string elementsindicated generally at 14 strung in a taut conduction across the frame.

In the modification of FIGS. 1 through 3, the racket frame includes anannular recessed portion 16 having a plurality of holes 18 formed in themedian plane of the racket and adapted to receive string elements 14.Referring particularly to FIGS. 2 and 3, each string element is extrudedor otherwise formed to have a generally triangular cross section andincluding a flat side 20 and an oppositely disposed apex 22. The stringreceiving holes 18 in frame 12 are likewise formed with a triangularcross section of a size and shape corresponding to that of the stringelements. The frame holes are all oriented in the same direction so thatthe flat faces 20 of the string elements constitute one racket facewhile the apices 22 constitute the opposite face of the racket.

Since all of the frame holes are oriented in the same direction, it isapparent that the flat portions 20 of the string elements constitute asmooth surface while the oppositely facing apices constitute a roughsurface.

Another variation of the invention utilizing the triangular crosssection type string is shown in FIGS. 4 and 5. In this case the racketframe 26 includes triangularly shaped grooves or slots 28 and 30 formedin the opposite or side faces thereof which are adapted to receivecorrespondingly shaped string elements having lengths 32 and 34 andconnecting portion 36. In this case, however, the frame grooves areformed so as to provide two sets of interwoven string elements or facesindicated generally at 38 and 40. Racket face 40 comprises the flatportions of the string elements which face outwardly in one directionwhile the other racket face 38 comprises the apices which face outwardlyin the opposite direction. In order to achieve this relationship, thetransverse common portion 36 of each string element, which is wrappedabout face element 26, is twisted whereby the outwardly facing apices ofracket face 38 are rotated to become inwardly facing in racket face 40.

With respect to the modifications of FIGS. 1 through 5, the designationsof smooth and rough surfaces refers respectively to the entire side orsurface comprised of the string portions or 40 (smooth) and 22 or 38(rough). For example, the greater coefficient of friction of the surfacecomprised of string portions 22 relative to the surface comprised ofportions 20 is due to apices or relatively sharp edges which incontacting a ball relatively tangentially impart a far greater spinthereto than when similarly engaged by the smooth surface by stringportions 20.

As an alternative to the triangularly shaped string elements of FIGS. 1through 5, it is possible to treat a conventional type racket string inthe manner illustrated in FIG. 6. In this case, string element 44 is ofconventional construction, e.g. substantially circular in cross section.In this modification the racket is strung in the conventional mannerbefore any treatment of a string surface is undertaken. However, afterthe racket is strung one surface of the racket is treated so as to berougher, or so as to have a greater coefficient of friction than theother face. One manner of achieving this result is to mask the facewhich is to remain smooth while applying an abrasive or gritty material46 to the other face of the racket. This result can be achieved byapplying a suitable adhesive or bonding substance to the unmaskedportions of the springs and thereafter sprinkling or otherwise applyingthe abrasive or gritty material to the adhesive. The bonding materialshould be of a type as to remain flexible so as not to crack or flakeoff as the strings flex during play.

After the gritty material is suitably bonded or adhered to the exposedportion of each string element and the masking material removed from theoppositely facing portions of the string elements, there results aracket having oppositely facing smooth and rough faces.

It is also within the scope of the invention to mechanically treat orform the strings of one face of the racket after the racket is strung togive said face a greater coefiicient of friction than the other face.This can be done by utilizing a suitable tool to impress indentations orserrations in the strings of one face to create the desired roughness orcoefficient of friction.

Thus, it is within the contemplation of the subject invention that othermeans may be utilized to create a racket having two ball-strikingsurfaces in which one surface has a substantially greater roughness orcoefficient of friction than the other face to thereby enable a playerto impart greatly different spins to a ball depending on which face isused to strike the ball during play.

The embodiments of the present invention in which an exclusive propertyor privilege is claimed are defined as follows:

1. A racket including a frame and a plurality of string elementssupported upon said frame in a taut open weave pattern, each stringelement including first and second discrete portions extendingsubstantially throughout the length thereof, the first discrete portionsof said string elements coacting to form a first ball-engaging surface,the second discrete portions of said string elements coacting to form asecond ballengaging surface, said first ball-engaging surface having ahigh coefficient of friction relative to said second ball-engagingsurface.

2. A racket as set forth in claim 1 in which each string element ispreformed to provide said first and second discrete portions.

3. A racket as set forth in claim 2 in which the string elements have agenerally triangular cross section, one side of said string elementcomprising said second discrete portion, the apex opposite the said oneside of said string element comprising said first discrete portion.

4. A racket as set forth in claim 3 in which said frame includes aplurality of triangularly shaped openings formed therein andcorresponding in shape and size to the triangular cross section of saidstring elements, each string element being supported between a pair ofaligned frame openings.

5. A racket as set forth in claim 4 in which said frame includes amedian plane intersecting said triangularly shaped openings.

6. A racket as set forth in claim 3 in which said frame includes amedian plane, first and second sets of aligned triangularly shapedopenings formed in said frame and disposed on opposite sides of saidmedian plane, said openings corresponding in size and shape to thetriangular cross sections of said string elements, each string elementbeing supported between aligned openings of said first and second setsof frame openings whereby the first and second ball-engaging surfacesare respectively spaced on opposite sides of said median plane.

7. A racket as set forth in claim 1 in which each string element has agenerally circular cross section, the first and second discrete portionsof each string element comprehending substantially one-half of thestring circumference.

8. A racket as set forth in claim 7 in which the first discrete portionof each string element has a substantially greater coefficient offriction than the second discrete portion.

9. A racket as set forth in claim 7 in which a particulate material isadhered to the first discrete portion of each string element.

1. A racket including a frame and a plurality of string elements supported upon said frame in a taut open weave pattern, each string element including first and second discrete portions extending substantially throughout the length thereof, the first discrete portions of said string elements coacting to form a first ball-engaging surface, the second discrete portions of said string elements coacting to form a second ball-engaging surface, said first ball-engaging surface having a high coefficient of friction relative to said second ball-engaging surface.
 2. A racket as set forth in claim 1 in which each string element is preformed to provide said first and second discrete portions.
 3. A racket as set forth in claim 2 in which the string elements have a generally triangular cross section, one side of said string element comprising said second discrete portion, the apex opposite the said one side of said string element comprising said first discrete portion.
 4. A racket as set forth in claim 3 in which said frame includes a plurality of triangularly shaped openings formed therein and corresponding in shape and size to the triangular cross section of said string elements, eAch string element being supported between a pair of aligned frame openings.
 5. A racket as set forth in claim 4 in which said frame includes a median plane intersecting said triangularly shaped openings.
 6. A racket as set forth in claim 3 in which said frame includes a median plane, first and second sets of aligned triangularly shaped openings formed in said frame and disposed on opposite sides of said median plane, said openings corresponding in size and shape to the triangular cross sections of said string elements, each string element being supported between aligned openings of said first and second sets of frame openings whereby the first and second ball-engaging surfaces are respectively spaced on opposite sides of said median plane.
 7. A racket as set forth in claim 1 in which each string element has a generally circular cross section, the first and second discrete portions of each string element comprehending substantially one-half of the string circumference.
 8. A racket as set forth in claim 7 in which the first discrete portion of each string element has a substantially greater coefficient of friction than the second discrete portion.
 9. A racket as set forth in claim 7 in which a particulate material is adhered to the first discrete portion of each string element. 